The sappers – soldiers who perform a variety of military engineering duties – also deployed to the Otterburn army training area for another testing challenge, which included crossing rivers using special bridging equipment.

The 10-day exercise scenario placed the troops in a humanitarian relief operation in a country facing famine and struggling to recover from damage caused by a tsunami, with Government control undermined by insurgents. Sappers from 23 Engineer Regiment (Air Assault) travelled to Northumberland from their base in Suffolk to join forces with French troops from 17e Regiment du Genie Parachutiste.

The first phase of the exercise involved the soldiers using portable ferry bridge equipment to move vehicles and personnel across two miles of Kielder Water in a shuttle-style operation.

After moving to Otterbun, they were challenged to build water supply points capable of providing 40,000 litres of drinking water every day. They also had to cross rivers using bridging equipment and improvised materials, and build defensive positions which were then attacked by ‘enemy’ forces.

The training was intended to test the unit in its role of providing combat engineering support to 16 Air Assault Brigade, which is ready to deploy anywhere in the world at short notice for operations ranging from disaster relief to war fighting.

Lt Col Jason Hones, commanding officer of 23 Engineer Regiment (Air Assault), said: “Exercise Eagle Sapper has seen our soldiers working for up to 22 hours a day on demanding tasks, that test both their combat engineering and infantry skills in very harsh terrain and weather conditions.

“It is important that we test the mettle of the soldier we are going to send on operations in arduous and unknown conditions, so that we know he can cope with anything that is thrown at him. If a soldier can survive in Northumberland in winter he can survive anywhere in the world.”

The French troops joined the exercise as part of the developing partnership between 16 Air Assault Brigade and 11e Brigade Parachutiste, which have been tasked to develop a combined joint expeditionary force.

Lt Col Hones said: “We're really lucky to have soldiers from our French partner regiment with us, having recently sent troops over to train in France. “Working together on this exercise is developing our integration at the section level, to learn how we each operate and our particular strengths and weaknesses.”